BACKGROUND: Intramuscular injections (depot preparations) offer an advantage over oral medication for treating schizophrenia by reducing poor compliance. The benefits gained by long acting preparations, however, may be offset by a higher incidence of adverse effects. OBJECTIVES: To investigate the clinical effects of fluphenazine decanoate and enanthate. SEARCH STRATEGY: For this update we searched the Cochrane Schizophrenia Group's Register (May 2002). SELECTION CRITERIA: We considered all relevant randomised clinical controlled trials focusing on people with schizophrenia comparing fluphenazine decanoate or enanthate with placebo or oral anti-psychotics or other depot preparations. DATA COLLECTION AND ANALYSIS: We reliably selected, quality rated and data extracted studies. For dichotomous data we estimated relative risk (RR) with 95% confidence intervals (CI), and, where possible, the number needed to treat/harm (NNT/H). Analysis was by intention-to-treat. We used the weighted mean difference (WMD) for normal continuous data. Tests of heterogeneity and for publication bias were undertaken. MAIN RESULTS: This review now includes 70 randomised studies. Compared with placebo, fluphenazine decanoate did not reduce relapse over 6 months to 1 year, but one longer term study found that relapse was significantly reduced in the fluphenazine arm (n=54, RR 0.35, CI 0.2 to 0.6, NNT 2 CI 2 to 4). Fluphenazine decanoate does not reduce relapse more than oral neuroleptics (n=419, 6 RCTs, RR relapse 26-52 weeks 1.46 CI 0.8 to 2.8) or other depot antipsychotics (n=581, 11 RCTs, RR relapse 26-52 weeks 0.82 CI 0.6 to 1.2). Relapse rates over 6 months to 1 year were not significantly different between standard dosage of fluphenazine decanoate over a low dose group (n=523, 4 RCTs, RR 2.09 CI 0.6 to 7.1). Movement disorders were significantly less for people receiving fluphenazine decanoate compared with oral neuroleptics (n=259, 3 RCTs, RR 0.47 CI 0.2 to 0.9, NNT 14 CI 10 to 82).For fluphenazine enanthate there were limited data but no clear difference in global change (0 to 5 weeks) when compared with oral neuroleptics (n=31, 1 RCTs, RR 0.67 CI 0.3 to 1.7), and in relapse rates over 6-26 weeks between fluphenazine enanthate and other depots. Compared with placebo, giving the enanthate caused no more people to need need anticholinergic drugs (n=25, 1 RCT, RR 9.69 CI 0.6 to 163.0) and movement disorders, tardive dyskinesia, tremor, blurred vision and dry mouth were equally prevalent when enanthate was compared with other depot neuroleptics. AUTHORS' CONCLUSIONS: There are more data for fluphenazine decanoate than for the enanthate ester. Both are effective antipsychotic preparations. In the context of trials, there is little advantage of these depots over oral medications in terms of compliance but this is unlikely to be applicable to everyday clinical practice.